The Groovy Log.java source code

/*
* Copyright 2003-2010 the original author or authors.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package groovy.util.logging;
import org.codehaus.groovy.ast.ClassHelper;
import org.codehaus.groovy.ast.ClassNode;
import org.codehaus.groovy.ast.FieldNode;
import org.codehaus.groovy.ast.expr.*;
import org.codehaus.groovy.transform.GroovyASTTransformationClass;
import org.codehaus.groovy.transform.LogASTTransformation.LoggingStrategy;
import org.objectweb.asm.Opcodes;
import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;
/**
* This local transform adds a logging ability to your program using
* java.util.logging. Every method call on a unbound variable named <i>log
* will be mapped to a call to the logger. For this a <i>log field will be
* inserted in the class. If the field already exists the usage of this transform
* will cause a compilation error. The method name will be used to determine
* what to call on the logger.
* <pre>
* log.name(exp)
* </pre>is mapped to
* <pre>
* if (log.isLoggable(Level.NAME) {
* log.name(exp)
* }</pre>
* Here name is a place holder for info, fine, finer, finest, config, warning, severe.
* NAME is name transformed to upper case. if anything else is used it will result in
* an exception at runtime. If the expression exp is a constant or only a variable access
* the method call will not be transformed. But this will still cause a call on the injected
* logger.
*
* @author Guillaume Laforge
* @author Jochen Theodorou
* @author Dinko Srkoc
* @author Hamlet D'Arcy
* @author Raffaele Cigni
* @author Alberto Vilches Raton
* @since 1.8.0
*/
@java.lang.annotation.Documented
@Retention(RetentionPolicy.SOURCE)
@Target({ElementType.TYPE})
@GroovyASTTransformationClass("org.codehaus.groovy.transform.LogASTTransformation")
public @interface Log {
String value() default "log";
Class<? extends LoggingStrategy> loggingStrategy() default JavaUtilLoggingStrategy.class;
/**
* This class contains the logic of how to weave a Java Util Logging logger into the host class.
*/
public static class JavaUtilLoggingStrategy implements LoggingStrategy {
public FieldNode addLoggerFieldToClass(ClassNode classNode, String logFieldName) {
return classNode.addField(logFieldName,
Opcodes.ACC_FINAL | Opcodes.ACC_TRANSIENT | Opcodes.ACC_STATIC | Opcodes.ACC_PRIVATE,
new ClassNode("java.util.logging.Logger", Opcodes.ACC_PUBLIC, ClassHelper.OBJECT_TYPE),
new MethodCallExpression(
new ClassExpression(new ClassNode("java.util.logging.Logger", Opcodes.ACC_PUBLIC, ClassHelper.OBJECT_TYPE)),
"getLogger",
new ConstantExpression(classNode.getName())));
}
public boolean isLoggingMethod(String methodName) {
return methodName.matches("severe|warning|info|fine|finer|finest");
}
public Expression wrapLoggingMethodCall(Expression logVariable, String methodName, Expression originalExpression) {
ClassNode levelClass = new ClassNode("java.util.logging.Level", 0, ClassHelper.OBJECT_TYPE);
AttributeExpression logLevelExpression = new AttributeExpression(
new ClassExpression(levelClass),
new ConstantExpression(methodName.toUpperCase()));
ArgumentListExpression args = new ArgumentListExpression();
args.addExpression(logLevelExpression);
MethodCallExpression condition = new MethodCallExpression(logVariable, "isLoggable", args);
return new TernaryExpression(
new BooleanExpression(condition),
originalExpression,
ConstantExpression.NULL);
}
}
}

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